Dog brains rotated by selective breeding

The selective breeding of some domestic dogs has made their brains rotate forwards, and relocated one key component.

Michael Valenzuela at the University of New South Wales in Sydney, Australia, and colleagues, used a brain scanner to look at the heads of 11 dogs that had recently been put down, and two live ones. The dogs came from a variety of breeds, which have been bred over thousands of years to have – among other characteristics – snouts of different lengths.

They found that dogs with shorter snouts had brains which were rotated forwards by up to 15 degrees. They also found that the olfactory lobe at the front of the brain, which processes the sense of smell, was shunted downwards.

Convincing glance

"As a dog's head or skull shape becomes flatter – more pug-like – the brain rotates forward and the smell centre of the brain drifts further down to the lowest position in the skull," Valenzuela says. "It's something that hasn't been documented in other species."

"This is the first evidence to suggest that selective breeding to meet specific physical characteristics in breed standards has had an impact on brain organisation," says Lisa Collins of the Royal Veterinary College in Hatfield, UK. It might help explain why long-snouted dogs are better at scent work, such as sniffing out drugs, than short-snouted breeds, she says.

She added: "We do not know what effect, if any, such a reorganisation of the brain might have on the health of different dog breeds."

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Look at my face. Is it any wonder my brain moved? (Image: falcatraz/iStock)